Displaying 20 results from an estimated 6000 matches similar to: "Strange behaviour of spectrum()?"
2000 Feb 01
1
plotting spectrum of time series etc
Hi, everyone, I tried to use "spectrum()" or "spec.pgram()" to get a
periodogram of a time series but they didn't work.
Even the examples given in the help file didn't work (all with the same
error message, below). And the 'ts'ibrary was
loaded with "library(ts)" or "library("ts"). I also tried
library(tseries) but got the same problem.
1999 Jul 19
9
time series in R
Time Series functions in R
==========================
I think a good basic S-like functionality for library(ts) in base R
would include
ts class, tsp, is.ts, as.ts
plot methods
start end window frequency cycle deltat
lag diff aggregate
filter
spectrum, spec.pgram, spec.taper, cumulative periodogram, spec.ar?
ar -- at least univariate by Yule-Walker
arima -- sim, filter, mle, diag, forecast
2011 Sep 23
1
Cross Spectrum : Conversion of 2-D spectrum into a single complex array
Hi, I'm wondering why the spectrum() phase of quadrature
couple isn't purely +/-pi.
But mostly, I'm looking for a recommended way to take a 2-D
spectrum and convert it into a single complex array.
Kindly consider:
# 10 Hz sine wave 10 seconds long sampled at 50 Hz
deltaT = 1/50
t = seq(0, 10, deltaT)
w = 2 * pi * 10
x = ts( sin( w * t ), deltat = deltaT )
y = ts( sin(
2005 Dec 01
1
squared coherency and cross-spectrum
Hi All,
I have two time series, each has length 354. I tried to calculate the
coherency^2 between them, but the value I got is always 1. On a website,
it says: " Note that if the ensemble averaging were to be omitted, the
coherency (squared) would be 1, independent of the data". Does any of
you know how to specify properly in R in order to get more useful
coherency? The examples in
2008 Sep 09
4
Help with 'spectrum'
For the command 'spectrum' I read:
The spectrum here is defined with scaling 1/frequency(x), following S-PLUS. This makes the spectral density a density over the range (-frequency(x)/2, +frequency(x)/2], whereas a more common scaling is 2? and range (-0.5, 0.5] (e.g., Bloomfield) or 1 and range (-?, ?].
Forgive my ignorance but I am having a hard time interpreting this. Does this mean
2011 May 10
1
Power Spectrum from STFT (e1071)?
Hello.
Does anyone know how to generate a power spectrum from the STFT function in
package e1071? The output for this function supplies the Fourier
coefficients, but I do not know how to relate these back to the power
spectrum.
Alternatively, if anyone is aware of other packages/functions that perform
short time Fourier transforms, that would also be helpful.
Thanks.
--
View this message in
2013 Dec 18
1
how to analysisi spectrum of a dataset with NA value
hi R users
I have a large 1D dataset and some of them is NA value .
I found I cound get the spectrum by such a command.
ua=c£¨10£¬30 £¬40£¬50£¬NA£©
spectrum(ua)
and I could not use na.rm just like mean or sd function
How could I get the spectrum of ua ?
thank you .
--
TANG Jie
[[alternative HTML version deleted]]
2011 Feb 08
1
Recuperate Spectrum() amplitude
Dear list,
I apologies first for my English, hope you will understand well my question.
I am working on 1/2 hour piezometric data, time unit is second. They
present daily oscillation when using the spectrum() function. What I am
really interested in, is to find the amplitude corresponding to this
oscillation.
I work with a college using Matlab, and although we apply the same
methodology, our
2008 Apr 30
3
Cross Spectrum Analysis
I am reading some documentation about Cross Spectrum Analysis as a technique
to compare spectra.
My understanding is that it estimates the correlation strength between
quasi-periodic structures embedded in two signals. I believe it may be
useful for my signals analysis.
I was referred to the R functions that implement this type of analysis. I
tried all the examples which generated a series of
1999 Jul 08
1
new time series package available
Fritz just put the first version of a new time series package to the
contrib section at CRAN.
The package is called "tseries.tgz" and provides a library for time
series analysis. It contains
acf Autocorrelation Function
adf.test Augmented Dickey-Fuller Test
amif Auto Mutual Information Function
bds.test BDS Test
1999 Jul 08
1
new time series package available
Fritz just put the first version of a new time series package to the
contrib section at CRAN.
The package is called "tseries.tgz" and provides a library for time
series analysis. It contains
acf Autocorrelation Function
adf.test Augmented Dickey-Fuller Test
amif Auto Mutual Information Function
bds.test BDS Test
2004 Jan 22
1
spectrum
Dear R users
I have two questions about estimating the spectral power of a
time series:
1) I came across a funny thing with the following code:
data(co2)
par(mfrow=c(2,1))
co2.sp1<-spectrum(co2,detrend=T,demean=T,span=3)
co2.sp2<-spectrum(co2[1:468],detrend=T,demean=T,span=3)
The first plot displays the frequencies ranging from 0 to 6
whearas the second plot displays the same curve but
2008 Oct 10
1
multi-scale singular spectrum analysis (SSA)
Hi everybody!
I am searching for an R implementation of multi-scale singular
spectrum analysis (SSA), which was introduced by Yiou etal (2000)
(Data-adaptive wavelets and multi-scale singular-spectrum analysis)
and further described in Ghil etal (2002).
For SSA alone I found an package recently published on r-forge:
http://r-forge.r-project.org/projects/simsalabim/
I am happy about any
2007 Mar 09
2
Deconvolution of a spectrum
Dear useRs,
I have a curve which is a mixture of Gaussian curves (for example UV
emission or absorption spectrum). Do you have any suggestions how to
implement searching for optimal set of Gaussian peaks to fit the curve?
I know that it is very complex problem, but maybe it is a possibility
to do it? First supposement is to use a nls() with very large functions,
and compare AIC value, but it is
2004 Jul 15
1
Spectrum Analyizer software
This was an interesting post from another list
I'm on. I think that with all of the echo
cancellation discussion happening, that someone
perhaps might be on the lookout for this type of
software, so this post was well-timed for
Asterisk uses. It is perhaps the case that those
of you working on volume/echo/etc stuff might
find this useful towards your goals.
JT
>To: [snip]
2004 Aug 06
1
Frozen upper spectrum in WB VBR CNG
Hi,
I've been using Speex in my voice-over-IP program on Win32, in
wideband (16kHz) mode. I just starting using VBR recently and
have run into something that might be a problem within Speex:
If someone hasn't spoken for a little while, and the bitrate drops
to very low, sometimes the high half of the spectrum becomes frozen
with a looping sound. The bottom half of the spectrum is
2010 Mar 22
1
Add title to color spectrum legend in xyplot
Hi,
I have a plot that is essentially the same as that in Figure 5.6 of "Lattice
- Multivariate Data Visualization with R". The key difference is that I
would like to add a title to top of the grey color spectrum legend, but have
thus far been unsuccessful. I've tried a variety of options, but to no
avail. I'm new to R, and admittedly I don't understand the
2004 Aug 06
1
Frozen upper spectrum in WB VBR CNG
Jean-Marc Valin (jean-marc.valin@hermes.usherb.ca) wrote:
>
> > I've been using Speex in my voice-over-IP program on Win32, in
> > wideband (16kHz) mode. I just starting using VBR recently and
> > have run into something that might be a problem within Speex:
>
> Are you turning on DTX in addition to VBR? Also, what version are you
> using. As of 1.0, DTX is
2003 Jun 16
1
Spectrum duplication (2)
Reading Monty's message, I better re-post this one :-).
In another thread the following was said:
> It might help if you also mentioned that the sound quality of Ogg is
> significantly better than MP3 (assuming that you use regular MP3, not
> MP3Pro), especially at 32kbps.
Speaking of which, would there be anything to stop Vorbis, maybe not v1
but in the future, to use similar
2004 Mar 05
2
Internal NA removal out of Time Series with na.omit.ts()
Hi R specialists,
The na.omit.ts() method fails when the time series contains internal
NA's. How can these automatically be removed?
> spectrum(ts.mNDII, na.action=na.omit)
Error in na.omit.ts(as.ts(x)) : time series contains internal NAs
How can the na.action be activated correctly?
> acf(ts.Lin, type=c("correlation"), na.action=na.omit)
Error in na.omit.ts(as.ts(x)) :